Pulse generator and distributor



H- G. FEISSEL PULSE GENERATOR AND DISTRIBUTOR April 30, 1957 4 Sheets-Sheet 2 Filed July 2, 1952 0 I 2 3 4 5 3 m B 0 B B A A B .B M HUN t|| k m MW w v MW w m y MW w H. G. FEISSEL 4 Sheets-Sheet 3 M a z mm m m w n i .nlfmlmv. x hm Q w 51+ @Q Q April 30, 1957 PULSE GENERATOR AND DISTRIBUTOR Filed July 2, 1952 April 30, 1957 H. e. FEISSEL 2,790,900

PULSE GENERATOR AND DISTRIBUTOR Filed July 2, 1952 4 Sheets-Sheet 4 R m 4 an n Qm 3 9x n m w lill r m i M a mi w w T+ m we QM. W w K H n n; mm

PULSE GENERATOR AND DISTRIBUTOR Henri Gerard Feissel, Paris, France, assignor to Compaguie des Machines Bull (Societe Anonyme), Paris,

The present invention concerns an impulse generating system receiving periodical pilot pulses through one particular controlling channel, or path and supplying a number N of trains of timing impulses.

These impulse trains, called timing trains should have the same period of recurrence T, same duty cycle and any of them should be delayed with respect to the other by time intervals equal to a fraction T/N of this period of recurrence.

, This system includes a number N of devices forming the N elements of a closed chain. Each device can supply two simultaneous trains of which one, called the inverted train, is composed of negative impulses, while the other, called the timing train, is composed ofpositive impulses. Each element is connected to at least two of the immediately adjoining elements as well as to a pilotpulse generator. This system is characterized by the pulses.

fact that coincidence detectors associated with the vari- The inverted train and the timing train which are produced by any one of the elements of the chain and which are represented in function of time in a system of rectangular coordinates in Figure l and are symmetrical one with another in respect to an axis passing through the middle of the amplitude of the impulses.

A generator of known type supplies the above defined system under control of a train of positive square pilot impulses cyclically recurring, each having a determined length in time which is equal to of each recurrence period p.

This system distributes'trapezoidal impulses over twice N output channels, the duration of which exceeds that of the pilot impulses. By way of unrestrictive example, a description of a system producing 4 timing trains and 4 inverted trains will now be given.

The recurrence period T of the timingimpulses supplied by 4 of the outputs of the system is equal to four times that of the pilot impulses and the lag of the 4 corresponding trains with respect to one of these is respectively equal to once, twice, three times and four 1 The invention has as its further object a system in y 2,700,000 Patented Apr. 30, 1957 lCe which each unit or element involves a device to stop timing impulses. This device responds to the coincidence of the absence of a pilot impulse with the presence of at leastone inverted impulse supplied by the next element in the chain.

In the drawing:

Fig. 1 shows part of the inverted and timing impulse trains.

Fig. 2 shows a block diagram of a system of four elements.

Fig. '3 shows an or gating device hereinafter termed bulfer.

Fig. 4 shows an and gating device hereinafter termed gate-9! Figs. 5 and 6 taken together show a detailed arrangement of a four element system.

' Fig. 7 shows part of the inverted and timing trains obtained'by means of a five element system. In Fig. 1, seven impulse trains may be seen. The top most, henceforth designated as train P, represents square impulses which constitute the above referred to pilot im- Their recurrence period p is equal to T/4 and their individual duration t is equal toiT/ 8. Their voltages vary from +V4 to V5. Impulse train B1, immediately under train P, represents trapezoidal timing impulses. They have a length in time of 3/ 8T or 3t. Impulse train B2, under train B1, represents a second timing impulse train whichshould be delaysd with respect to the. first one by a time interval equal to 2t or p. Train B3, under train Bz, represents an impulse train which should be delayed with respect to train B2 by a time interval also equal to 2t. Finally, train B4, under train B3, represents a timing impulse train which should be delayed with respect to train B3, by a time interval equal to 2t. The voltages of these four trains vary between the same values +V4, Va as those characterizing train P. Train Bz,. just under train B4, represents an inverted impulse train which is symmetrical with train B2 in respectto an axis mm passing through the middle plots r and r1 of pulse B2 wave fronts. Finally, inverted pulse train B3, under train B2, is obtained from train B3 by symmetry in respect to axis nn' passing through the middle plots 2 and q1" of B3 impulse wave fronts. The wave crest voltages of pulses B1 to B4 and of pulses B1 to B4 are equalvto +V4 while the voltages at their bases are equal to'- s.

Fig. 3 shows a buffer of a known typewith 3 inputs 1a, 2a, 3a, each of which comprises a rectifier cell, connected through g and resistor 5a to the negative terminal, at --V7 potential, of a source 4a whose positive terminal is grounded. The resistance of 5a is, for example, one thousand times that of the rectifier cells measured in the conducting direction.

If voltages whose algebraic values are much greater than -V7 are applied at inputs 1a, 2a, 3a, and if V1 V2 V3, point g automatically takes a potential slightly below V1. If V1=V2=Vs, point g remains at po tential V1. This is why a butter acts as a coincidence detector whatever the number of its inputs may be.

" Fig. 4 shows a gate of a known type with 3 inputs 6b, 7b, 8b. It differs from the buffer shown in Fig. 3 only in the poling of the cells which is reversed as are the connections between source 4a on one hand and ground and resistor on the other. In this arrangement if V4, V5, V0 stand for the algebraic values of the potentials at the 3 inputs and if V4 V5 Ve, the potential Vg at g, is automatically slightly over Vs. If V4=V5=Vs, Vg,= V, which shows that a gate also acts as a coincidence detector;

2.;Thesolid type rectifier cells of gates and bufiers being time of voltage application at their inputs.

Fig. 2 shows four generators A A A A, hereafter designated as timing impulse generators.

These generators are linked to the pilotirnpulse generator E respectively through leads2-e,, 3e 6-e,, '7e,, which are connected to supply line E7-2-6-3. They are also interconnected by means which are described hereafter. Any one of them, A, for instance, has .two outputs S and S which supply respectively impulse trains B and l3 shown in Fig. l. The simultaneous emission of timing and'inverted impulsesbygenerator A is made possible by the delaying connection 1'd which links output S, of generator A," to input a, of device A,. The holding of volt-age level of thesesame impulses is insurd 'by connectiomS-f :which'links output t, of generator A to input f, of generator.A,. The simultaneous emission of'timing and inverted'impulses bygenerator A, is made possible by .the delaying connection 12-12, which links output S, of generator A, to input d of generatonA The holding of voltage level of these same impulses is obtained by means of connection 8-f, linking output S: of .generaton A, to input f, of generator A,,.

Similarly, the'emission'ofimpulse trains B, and B, by generator A, is made possible by the delaying connection 9-41., linking output 8, of generator A,,-to the input a, of generator A,. The holdingof voltage level of these same impulses is'obtained by connection -11 1, linking output of generator A, to input f,. The delay linesrl, r2, r3 in connections l d 12d 9-d have delay values which are substantially equal to 1.5t. The simultaneous emission of a timing and of an invertedlirnpulse by generator A is determined by two non-delaying connections band c4. The holding of voltage level of these impulses is obtained by connection 4-f, which links output 8 of generator A to input 1, of generator A,. As may be seen from the time chart of Fig. 1, it is desired that thefirst timing train emitted at the beginning of a recurrence cycleT be produced by genorator-A "This is why connections such as c-15 and b-13' are established to represent starting conditions for generator A, which are different from those for other generators A A and A Figs. 5-6 show a mannerof practical realization-of the simplified diagram of Fig. 2. Identical elements in Fig. 2 andFigs. 5 6 bear same reference numbers. It followsthat in "Figs. 5-6, we shall find the impulse generators A, (Fig. 5), A (Fig. 5), A, (Fig. 6.),.-A, (Fig.6), each of which is included .in. a. rectangular area bounded by dots. and dashes. "Pilot impulse generator 16 (Fig. 5 is of a' known type. It is represented by arectangle. Its upper output terminal isfreturne'cl to'a negative voltage 'V through'line'16a,"71,'55 to an intermediate tap in source S, and itslower -output terminal 16b furnishes a trainof pilot impulses similar to train Pin Figjl. The lower and upper-voltages of these impulses are equal to V, and +V, voltage +V, 'being' that of the intermediate tap s, in source '18. Connections I7e,, 197e,, 21.e, and .23-e, distribute these impulses to generators A,, A A,,, A,,.

If we consider, generator A for instance, .it will be seen that this generator is provided with two outputs S. and S7 the output 8 being connected to. an output wire 20. Timing-impulse train B is available; onsoutput 5,, as well as on output wire 20. This outputwire 20 is connected, through delay-line 25, thedel'ay value of which is equal to.1-.5t, to. input d of generator.--A,. Input d of. generator A is connected -.to '.the output wire 18. of generator A, through delay line 24 which does not appreciably differ from the above-mentioned delay line'25. Outputs 18=and1- Spare twin outputs and 7 both furnish B impulse trains.

Connection 18-d, corresponds to connection 1-d,,.,in Fig. 2.

Lower input f of generator A is connected to output S,, of generator A through link 26-27 and thus corresponds to connection S-f in Fig. 2.

Output S of generator A is connected to input f, of generator A through line 2829 and'so corresponds to connection 4-f, in Fig. 2.

Generator A, (Fig. 6) has three inputs 11,. 12,, f, and

outputs 5,, 22 and 57, which, as will be seen below, are quite comparable respectively to inputs d,, e. f and outputs S 20 and of generator A,. It has been stated above that input (I, is connectedto output wire 20 of generator A, and that input e, is connected to generator 16. Input f, is connected to output S, of generator A, through line 3031. This connection corresponds to the connection 8- in Fig. 2.

Output wire 22, which is one of the twin outputs of A, is connected to input d, of generator A, through delay line 32 which does not appreciably differ from delay lines 24 and 25. The output wire 22 delivers the impulse trains B Output is, as has been said above, connected to input 1, of generator A,.

Generator A4 has, as in Fig. 2, three inputs'f e,, d, and two outputs S4 and S4. It has been explained above that input d, is connected to output wire wire 22 of generators A3 and that input e, is connected to genererator 16. Input 1, is connected to output 31 of generator A1 byline 33, 34. As has been said above, output i is connected to input f, of generator As.

It will be seen hereafter that the similarity established between Fig. 2 and Figs. 5-6 is again born out with respect to generator A1 which has four inputs b, c, 'e,, f,,

and three outputsSr. 18 and 1. Input b is connected to output S, of generator A3 by line 35, 36, 26. Input 0 is connected to output of generator Az by line 37, 29, 28. It is already known that input e is connected to generator 16, that input f, is connected to output z of generator A2 and that output wire 18 is connected to input d, of generator A2.

By way of example and with the help of Fig. l, the set-up and operation of generator As (Fig. 6), which are quite similar to those of the other generators, will now be described. This generator A3 mainly includes a pentodeof which the input circuit 39, 40, 41, 42, 43, across controlgrid 44 and cathode 43, isconnected to three inputs d 2,, f,,. "The output circuit 45, 46, 47, 48, 49, across plate 45 and screen grid 49 of the pentode, includes .the primary winding 50a of a transformer with three secondary windings 56b, 50c and 50:1. The rotational directional directions and the external connections of the transformer windings are such that when a negativegoing pulse appears across primary winding 500, a negative-goingpulse is available across secondary winding 50b and a positive-going pulse is available across each of the other secondary windings 50c and 50d. Windings 50c and 50:! are connectedby their upper terminals to tap s, of source S through line 55-s The set-up of pentode 38 is characterized by the fact that it.comprises a positive feedback circuit 52, 53, 54, 50d, 55, s which includes resistor 54 and winding 50!! already mentioned. The voltage at terminal 53, which is grounded through a voltage limiter 99 including a rectifier cell 990- and a source 99b of E. M. F. equal to +V4, cannot exceed the value +V4. A resistor 56 in the cathode circuit provides a grid-bias voltage aproximately equivalent to the voltage of battery 99/). Plate circuit 45, 46, 47, 48, 49 of pentode 38 is connected at point 46 to the cathode ofdiode 77,

k the plate of which is connected through-connection 59's,,

LQf a. double diodetilof'which the cathode is. connected,

arsonoe to the positive terminal s, of source S through line 62-s Lastly, this same plate circuit is linked to intermediate tap s, of source S, through connection 48-78-s It can be. seen that the voltage at point 46 of the plate circuit can neither be lower than |V3 nor higher than +V1 without, in the first case, setting diode 77 into operation and, in the second case, setting diode 61 into operation. Actually, while in operation, the internal resistance of these diodes is negligible. The control grid of pentode 38 may receive a positive voltage (1) from gate 63 through the crystal diode 64; (2) from buffer 66 through the crystal diode 66b; (3) from the positive feedback circuit through the wire between points 53 and 52. Gate 63 is composed of crystal diodes 63a, 63b and of resistor 68; buffer 66 is composed of crystal diodes 66a, 66c, 66b and of resistor 67.

Before studying the operation of generator As, it is worth to note that generators A1, A2 and A4 are set up like A and that consequently maximum and minimum voltages at their outputs are the same as those of the corresponding outputs of generator As.

It has been pointed out above that pilot impulses have two levels respectively equal to V5 and +V4. When generator A3 does not generate any timing pulse, the output voltage of winding 50b is equal to +V4. The limitation by diodes 77 and 61 of the E. M. F. induced into winding 50!; by a positive impulse applied at input 39 of pentode 38 is such that the voltage at the output S3 of this winding cannot be lower than V5. Voltage limiters 72, 74, 75, each comprising a rectifier element indexed aand a source indexed b supplying a constant voltage +V4, respectively ground the outputs of delay lines 25, 32 and 24. Thus B2 impulses arriving at a' and delayed by 1.5t due to delay line 25 also vary between the same levels Va and +V4 as the pilot impulses, since the winding which produces them is subject to the same voltage V5 as winding 50d of generator A3.

Impulses 51, received at input f,,, vary between the same levels +V4 and -V5 as impulses B3 supplied by winding 50b. If it is assumed that the four generators A1-A4 are suitably connected to power sources, among which only source S is shown by Fig. 6, and that pilot pulse generator 16 is inoperative, none of these generators can deliver timing pulses. In these conditions, in the generator A3, for instance, the inputs d: and ea are at potential V5 and input 1, at potential +V4. By reason of the characteristics of gate 63, terminal 39 is at a potential slightly under V5 and, by reason of the characteristics of the butter 66, the terminal 65 is at a potential' slightly under +V4. Due to the values of the volttages +V2, of tap s of source S, and Vs, at the lower terminal of this source, which are respectively applied at terminals 69 and 40 of lines 69, 68, 64, 39, 65, 40, a plate to cathode current of very small intensity flows in pentode 38 when the above mentioned system is at rest.

In order to explain how the pulses of one timing train are generated, it will be assumed that the timing generator unit is already set into normal operation, under control of the pilot pulse generator 16. Figures 1, 5 and 6 will be referred to. For instance, considering the operation of generator As, it may be seen that, at a time 1.5t after the instant t, of front edge of pilot pulse n+1, input d,'(Fig. 6) receives a positive pulse derived from the preceding timing pulse B2 through delay network 25 (Fig. 5). A little time after, that is at instant t,, input 2,, receives the pilot pulse n+2, thus setting gate 63 in a transmitting condition. The positive pulse transmitted through diode 64 to the control grid 44 of pentode 38 makes the latter heavily conducting. The resulting flow of anode current causes a negative-going pulse to appear across the primary winding 50a, the potential of anode 45 not dropping,-however, below voltage +V3, due to limiting diode 77. Consequently induced pulses appear across the secondary windings. Specially a positive timthe normal output terminal S1 of generator A1.

ing pulse B3 is available on output wire 22 of winding 500. A negative pul se induced across secondary winding 50b causes output S3 to be brought at potential -V5. A positive pulse induced across secondary winding 50d also permits the application of a positive voltage to the control grid through 54, 53 and 52, although its amplitude is lessened by resistor 54.

When the pilot pulse n+2 ceases at instant t gate 63 assumes its blocking condition. However during the gap between pilot pulsesn+2 and n+3, a positive voltage is still maintained upon the control grid of the pentode because this voltage is transmitted through diode 66b and diode 66c of buffer 66 from input f,. As a matter of fact, as long as a timing pulse B4 is not produced, the voltage of output S4. remains positive. Thereafter a positive voltage is still maintained upon the control grid of the pentode, said voltage resulting from the pilot pulse n+3 transmitted through diodes 66b and 66a of buffer 66 from input a When the pilot pulse n+3 ceases at instant t the timing pulse B3 can no longer be continued because at this time all the inputs of the gating devices of A3 receive negative voltages. Although a positive'voltage is still transmitted at this instant to the control grid by the feedback circuit, this voltage vanishes through diodes 66b and 66c, since now output S4 is at a negative potential.

]t is to be observed that the feedback circuit in each timing generator represents only a security device against the possible impairings in the form of the pilot pulses. For instance if the duration of a pilot pulse were accidentally shortened, the feedback voltages would prevent the voltage on the control grid to drop substantially below voltage +V4.

As it is desired that generator A1 be the first to start operating at the outset of the operation, the gating devices controlling its input have starting conditions which difier from those for all the other generators.

7 As may be seen from Fig. l, the starting condition for generator A1 can be that both generators A2 and A3 be not emitting timing pulses. This condition, which is valid at the beginning of the operation, is still valid in the course of the normal operation of the generator unit.

In the timing pulse generator A1 the and gating device which controls its input has a structure and a manner of connection which difier from those of the three other generators. All its other elements are similar to those of the other generators.

Said and gating device or gate 86 has three inputs 0, b and e,, and comprises the diodes 86c, 86b and 86a. The output of gate 86 is connected through diode 93 and wire 71', 96 to the control grid of pentode 85. The input c is connected through the link 37, 29 and 28 (Fig. 5) to the inverted output .52 of generator A2. The input b is connected through the link .35, 36, 26 (Fig. 5), 27 (Fig. 6) to the inverted output S3 of generator A3. The input e, receives the pilot pulse train due to its connection to pilot pulse generator 16, through link 16b, 17.

The or gating device or buffer 89 comprises the diodes 89a, 89b, 890 whose connections are identical to those for the other generators.

It is again assumed that the four generators A1A4 are suitably connected to power sources. When pilot pulse generator 16 begins to supply pilot pulses to the inputs of the four generators, only gate 86 of generator A1 can assume a pulse transmitting condition. As a matter of fact, at the instant t when the pilot pulse n reaches the inputs e e inputs b and c of generator A1 receive a positive voltage +V4, while inputs d2, d and d4 respectively of generators A2, A3 and A4 receive a negative voltage V5, since no timing pulse has yet been generated.

Thus one first timing pulse of train B1 can appear at The sustaining of the voltage level and stoppage of this timing 7 pulse are performed'by the bulfer-89-under conditions equivalent to those described when explaining the operation of generator A3. r

This "first pulse Br, when transmitted with a delay of 1.5: to theinput d of generator A2, constitutes the starting condition for the second generator to become operative upon reception of the following pilot pulse n+1. Thereafter the sequential operation of the four generators can go on normally.

The special connection of the and gating device of generator A1 .is intended to avoid the use of an external device for automatically starting this generator before the others. In other embodiments the number N of generators in the timing generator unit could be smaller or greater than four. As a rule the inputs of said gating device should comprise, besides an input for receiving the pilot pulses, N2 inputs to beconnected respectively to the invertedoutputs of all the generators, the first and the latest of the series excepted.

-Needless to say that the manner of realization represented in Figs. 6 is but an unrestrictive example and that the Fig. 4 diagram may be practically realized in many' other ways within the scope of the invention. In particular the and gating device 86 associated in the present example with generator A1 may be included in any one of the other three. If it is included in generator A2, for example, inputs [1 and c of the latter must be connected to outputs S4 and S3 respectively and output 18 of generator A1 must be eliminated. Generator A1 Will receive delayed impulses S4 through an input a not shown. The same block diagram may be readily applied to a system composed of n impulse generators provided the period of recurrence p of the pilot impulses be equal to T/n instead of T/4 as above. The duty cycle of the timing impulses will then be equal to 3/212 and one of the generators, whatever its rank 1', will be associated with a locking device similar to gate 93 of generator A1 in Fig. 5. Fig. 7 shows a part of the impulses for a system comprising 5 generators A1 to As, the first of which is locked by impulses B2, B3 and lit. An impulse generating system according to the invention may be especially used in electronic computing machines of the series type for the control of the different stages in the elementary operations for addition and subtraction. The impulse generating system which has been described above may beused advantageously in computing machines operating by electric impulses. These impulses called numerical impulses, must always coincide with one of the above defined timing impulses.

I claim:

1. Pulse generator unit for generating an integer number N of shifted timing pulse trains having a common recurrence cycle of duration T and being shifted in time with one another by a fraction T /N of their recurrence cycle, comprising a same number N of timing pulse generators; each generator including an electron discharge tube having a control electrode and an output electrode, a transformer having a primary winding connected to said output electrode, a normal output winding and an inverted output winding for respectively delivering a normal pulse and an inverted pulse whenever said control electrode is energized, a coincidence circuit with a first input, a second input and an output terminal for delivering a control signal only when its both inputs are energized, an or gating circuit with a first input, a second input and an output terminal for delivering a control signal upon energization'of either or both of its inputs, and connections for transmitting the control signals from said coincidence circuit and said or gating circuit to said control electrode; connections in each generator for applying to the first inputs of said coincidence circuit and or" gating circuit pilot pulses having a repetition period equal to said fraction T/N; and connections for mutually interconnecting said N generators in serieschain form in such a manner that, in one nth generator the second input of its coincidence circuit is connected to the normal outputof the transtormerin the n-lth, generator in. the series through a delay circuit with a delay time at least equal to the duration of one of said pilot pulses and that in the same nth generator the second input of its or gating circuit is connected to the inverted output of the transformer in the n+lth generator in the series.

2. Pulse generator unit as claimed in claim 1, wherein each of said generators comprises a further winding in said transformer and a regenerative feedback connection between said further winding and said control electrode so as to maintain the energization level of the latter in case of voltage variations during the gap between two consecutive pilot pulses.

3. Pulse generator unit for generating an integer number N of shifted timing pulse trains having a common recurrence cycle of duration T and being shifted in time with respect toone another by a fraction T/N of their recurrence cycle, comprising a same number N of timing pulse generators; each generator including an electric valve arrangement having a control input, a normal output and an invertedoutput for respectively delivering a normal pulse and an inverted pulse Whenever said control input is energized, a coincidence circuit with a first input, a second input and an output terminal for delivering a control signal only when its both inputs are energized, an or gating circuit with afirst input, a second input and an output terminal for delivering a control signal upon energization of either or both of its inputs, and connections for conveyingthe control signals of said coincidence circuit and said or gating circuit to said control input; connections in each generator for applying to the first inputs of said coincidence circuit and or" gating circuit pilot pulses having a repetition period equal to saidfraction T/N; and connections for, mutually interconnecting said. N generators in series-chain form including a connection between the second input of said coincidence circuit of a given oneof said generators and the normal output of the preceding generator in the series, said connection being made through a delay element with a delay time at least equal to, the duration of one of said pilot pulses, and a connection between the second input of said or gating circuit of said given generator and the inverted output of the succeeding generator in the series,

and similar connections for the other generators in the series.

4. Pulse generator unit as claimed in claim 3 wherein each of saidgenerators has a regenerative feedback connection linking a point of said electric valve arrangement to the output terminal of said or gating circuit in the same generator so as to compensate for the eventual voltage variation over said control input during the gap between two consecutive pilot pulses.

5. Pulse generator unit for generating an integer number N of shifted timing pulse trains having a common recurrence cycle of duration T and a time shift with respect to one another of a fraction .T/N of their recur rence cycle, comprising in combination a same number N of timing pulse generators; each generator including an electric valve arrangement provided with a control element, a normal output terminal and an inverted output terminal respectively responsive in opposite directions to the energization of said control element by delivering complementary pulses, an or gating circuit with a first input, a second input and an output terminal for delivering a control signal upon energization of either or both of its inputs, a coincidence circuit with a first input, a second input and an output terminal for delivering a control signal only when both its inputs are energized, the first inputs of both circuits receiving a common train of pilot pulses having a repetition period equal to said time shift, the output terminals of both circuits being connected to said control element; and interconnections arranged to couple said generators as a series-ring circuit in which,

for a generator considered as the nth in the series, a connection links the second input of the corresponding or gating circuit to the inverted output terminal of the 11+ lth the generator in the series and another connection links the second input of the coincidence circuit in the generator considered to the normal output terminal of the nlth generator in the series, the latter connection including a time delay network with a delay time at least equal to the duration of one of said pilot pulsesand smaller than said time shift, so that the generation of a timing pulse by one of said generators is started by one single pilot pulse once in the course of any recurrence cycle, said timing pulse being terminated in relation to the next following pilot pulse.

6. Pulse generator unit for generating an integer number N of shifted timing pulse trains having a common recurrence cycle of duration T and a time shift with respect to one another of a fraction T/N of their recurrence cycle, comprising a series of N timing pulse generators; each generator including an electric valve arrangement having a control input, a normal output and an inverted output for respectively delivering a normal or timing pulse and an inverted pulse whenever said control input is energized, an or gating circuit with a first input, a second input and an output terminal for delivering a control signal upon energization of either or both of its inputs, a coincidence circuit with a first input, a second input and an output terminal for delivering a control signal only when all its inputs are energized, the coincidence circuit of the first generator in the series having further inputs, connections for transmitting the control signals from said coincidence circuit and gating circuit to said control input, connections in each generator for applying to the first inputs of said coincidence circuit and gating circuit pilot pulses having a repetition period equal to said time shift; connections for mutually interconnecting said N generators in a series-chain form including, for each generator considered, a connection between the second input of the or gating circuit of this considered generator and the inverted output of the succeeding generator in the series, and including for each generator considered, except for the first generator in the series, a connection between the second input of its coincidence circuit and the normal output of the preceding generator in the series, the latter connection comprising a delay circuit with a delay time at least equal to the duration of any of said pilot pulses; and further connections for connecting the second and further inputs of the coincidence circuit of said first generator to the inverted outputs of the N2 following generators in the series respectively, so that only said first generator can generate the first pulse to define the beginning of a recurrence cycle.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,579 Pierce Nov. 11, 1952 2,541,932 Melhouse Feb. 13, 1951 2,595,378 Hertog et al. May 6, 1952 2,616,977 Staal Nov. 4, 1952 2,628,309 Hughes Feb. 10, 1953 2,631,194 Reeves Mar. 10, 1953 2,640,921 Hansell June 2, 1953 OTHER REFERENCES Article: Nimrod, by Stuart-Williams, pages 344-348 of Electronic Engineering, for September 1951.

Article: Diode Coincidence and Mixing Computers, by Chen; pages 511-514 of proceedings of IRE for May 1950. 

